Removal of sulphureted hydrogen from gas and apparatus therefor



1,528 477 May' lo 1927' E. W. SMITH ET AL REMOVAL OF SULPHURETED HYDROGEN FROM GAS AND APPARATUS THEREFOR Filed Nov. 14, 1925 Patented May 10, 1927.

UNITED STATES ,1,628,411 PATENT oFricE. n

ERNEST WOODHOUSE SMITH AND THOMAS CAMPBELL FINLAYSON, F LONDON, ENG- LAND, ASSIGNORS OF ONE-THIRD T0 WOODALL-DUCKHAM LIMITED, OF LONDON,

ENGLAND.

.REMOVAL OF SULPHURETED HYDROGEN A:FROM GAS AND APPARATUS THEREFOB.

Application filed November 14, 1925, Serial No This invention relates to processes of re: moving sulphureted hydrogen from gas which depend on the use ot' an absorbing liquor which requires regeneration by oxidat-ion to render it tit for re-use.

An object of the invention is to save space and power in installations for purifying vgases in which air/ is caused to bubble through the liquor for the purpose of regenerating it. Hitherto the liquor has been treated in aerating tanks,` which occupied much ground space, and from :these tanks the liquor was pumped to the top of the absorption towers in which it descended in counter current to the gas to he purified. Bythe present invention the aerating tanks are eliminated and the power absorbed in pumping is diminished.

Another object of the invention is to facilitate the oxidation of the spent liquor by conducting the aeration process under pressure.

e 'lhese'and other objects are achieved bv bringing the air into intimate contact with a column of the spent liquor, the` air being admitted at or near the foot of the column so as to -form a column of emulsion of air and spent washing liquor. Such a column of emulsion covers a small ground space, and the air entering near the base of the column is under a comparatively high presure and the regeneration process (in which the dissolved oxygen plays an important part), is favorably influenced. Furthermore the purifying air serves to raise the liquor in the manner of an air-lift, thus economizing power. y @ne mode of carrying out the invention consists in causing the s ent liquor from the gas-purification cham er to, ent-er the footof an air-lift of known type and in which an emulsion is formed between air and liquid. By this means a particularly oliective'ntermixing of the 'air and the liquor 45 is attained. Furthermore, `the air for the reeneration serves/to raise the liquor to the eight necessary to'permit it to ilow after Aregeneration into the upper portion of the e gas-purification chamber, thus rendering unnecesasry the use of separatev pumps for this purpose.

The' airlift may be in one or morevstages, 1 according to the height of the` column.

If the liquid is not sufficiently regener- 69,108,` and in Great Britain December 10, 1924.

ated by elevation through one column it may be allowed to flow through another column.

The process may be rendered continuous by causing .the spent liquo'r to pass continulously to the regenerating column, and returning the regenerated liquor continuously to the purification chamber.

The accompanying diagram will help to explain the invention. It represents an ab.- sorptiomtower in elevation in Fig. 1 and in plan in Fig. 2.

It is assumed that the washing liquor used is that commonly employed, namely a solution of an alkali (for instance, sodium carbonate) containing in suspension a compound of iron (for instance, ferrie hydroxide). This liquor absorbs sulphureted hydrogen from the gas, forming iron sulphide,

and during the subsequent regeneration by loxidation the iron sulphide again becomes iron oxide. v.

a is thealkaline absorption tower. 'lhe liquor charged with sulphide flows from the bottom of the tower by pipe b into the emule' sifier c of an air-lift where itis mixed with air .in known manner, the emulsion rising up pipe (Z into the separator e. Here the air. leaves theliquor which now flows down pipe f into the second emulsitier g. Having passed in like manner through a second separator h and athird emulsfier z', the liquor finallyl arrives at the third separator le at the top of the tower. Fromz lo the liquor Hows into compartment l (Fig. -f2) of the cylindrical tank m. From this compartment the\liquor, if it should require further regeneration, is allowed to flow down a pipe into' the emulsifier of an air-lift not here shown, but similar to z', and is raised therefrom'into a separator 7s', at the top of the tower, and so to com artment n. This course may be repeated wit i yet another emulsitier and separator k2, until the liquor `finally arrives'in compartment o, whence it flows into the distributors p of the absorption tower.

lihe sulphur produced by thevregeneration of .the liquor rises to the surface in the form of a frothy scum in each of the aforesaid compartments, and flows over into the axial ipe q. The pipe g is connected with a disc arge, not shown, which delivers the ksulphur and liquor accompanying it, into a ico lli

said invention and the best means we know of carrying the saine into practical effect, we claim:-

l. A pi'occs of regenerating spent liquor of the'kind herein referred to, which consists iii introducing air into the lower part of an upwardly moving column of the liquor so as to form an upwardly moving column of air and liquor.

9.. A process of regenerating spent liquor of the kind herein referred to, which consists in feeding the liquor to the lower part of a hollow column, injecting air into the liquor at the said part so as to cause a mixture of air and liquor to ascend the column and causing the mixture to discharge from the upper part of the column.

3. A process of regenerating spent liquor of the kind herein referred to, which `consists iii feeding the liquor to the lower part of a hollow columnI` injecting air into the liquor at the said part so as to cause a mixture of air and liquor to ascend the column, ausing the mixture to discharge from the upper part of the column into a vessel in which the air separates from the mixture, then causing the liquor to descend from the vessel to the lower part of a second hollow column and injecting air into the lower part of this` column to repeat the operation.

'4. The coinbiiiationof an absorption tower for removing sulphuieted hydrogen from gas by means of a washing liquor of the kind herein referred to, atank at the top of the tower for discharging liquor into the tower,4 a hollow column adapted to deliver vliquor from its upper part into the tank,

means for feeding liquor into the lower part of the column and means for injecting air into the liquor at the said lower part.

Thecombination of an absorption tower for removing sulphureted hydrogen from gas 'by means-of a washingl liquor of the kind herein referred to, a tank at the top of the tower for discharging liquor into the tower, a hollow column adapted to deliver liquor from its upper part into the tank, means for feeding liquor into the lower part 4of the column, means for injecting air into the liquor at the said lower part, and means for discharging from the said tank matter floating on the surface of the liquor therein.

G. rThe combination of au absorption tower for removing sulphureted hydrogen .from gas by means of a washing liquor of the kind hei-cin referred to, a tank at the top ot the maar?? tower for discharging liquor into the tower, an air-lift discharging into the tank, means for feeding liquor to the air-lift and a pipe lfofllow of liquor from. the tower to the air- '7'1- Tlie combination of an absorption tower for removing sulphureted hydro en from gas by means of a washing' liquor o the kind herein referred to, a tank at the top of the tower for discharging liquor into the tower, an air-lift discharging into the tank, means for feeding liquor to the air-lift, a pipe for kind herein referred to, a device for distributing liquor in the tower at the top thereof, a number of tanks at the top of the tower, an air-lift discharging into the first of the said tanks, means for feeding liquor to the air-lift, a second air-lift discharging into the `second of the said tanks, means for feeding to the second air-lift liquor which has been discharged into the irst of the said tanks, the liquor continuing to flow from one tank to another through au air-lift, and means for flow of liquoifroin the iinal tank to the said device for distributing liquor.

9. The combination of an absorption tower for removing sulphuieted .hydrogen from gas by means of a washing liquor of the kind herein referred to, a device for distributing liquor in the tower at the top thereof, a number of tanks at the top of the tower, an nir-lift discharging into the ist of the said tanks, means for feeding liquor to the air-lift, a second air-lift discharging into the second of the said tanks, means for feeding to the second air-lift liquor which has been discharged into the first of the said tanks, the liquor continuing "to flow from one tank to another through an air-lift, means for flow of liquor from the nal tank to the said device for distributing liquo'r and means for discharging from each`tank matter floating on the surface of the liquor therein.

lin testimony whereof we have signed our naines to this specification.

ERNEST WOlJiHOUSE SMlTH. THOMAS CAMPBELL FINLAYSON. 

